Equal-Loudness Contour

Last Updated: October 13, 2016

Definition - What does Equal-Loudness Contour mean?

Equal-loudness contour is a measure of sound pressure over a spectrum of frequencies that are perceived as being equally loud to the hearer when expressed as a pure, constant tone. The measurement for loudness is the ‘phon’ and this is determined by referencing equal loudness contours. These are also known as ‘Fetcher-Munson curves. These curves are defined in ISO 226:2003.

Safeopedia explains Equal-Loudness Contour

The concept of equal loudness contours is applied to hearing conservation measures. The ear is more sensitive to high frequency sound waves than it is to lower frequency sound waves, thus the actual effect on the human ear in terms of pressure exerted by sounds is taken into account. Data from the OSHA Integrated Management Information system recorded between 1979 and 2006 demonstrated that hazardous noise levels are present in all forms of industry, thus hearing conservation is a factor that must be considered by workplace health and safety professionals across all industries.